Asian fossils reveal humanity

Asian fossils reveal humanity's
giant cousin

by Russell L. Ciochon

For thousands of years, Chinese pharmacists have used fossils -
which they call dragon teeth and dragon bones - as ingredients in
potions intended to cure ailments ranging from backache to sexual
impotence. The fossil-rich caves of southern China have been, and
still are, sedulously mined by farmers, who sell these medicinal
treasures to apothecaries in the cities. In just such a pharmacy,
in Hong Kong in 1935, the German paleoanthropologist Ralph von Koenigswald
came across a large fossil primate molar that did not belong to
any known species. Over the next four years he searched further
in Hong Kong and Guangzhou (Canton) and found three more of the
oversize teeth, thereby establishing the existence of an extinct
ape, the largest primate ever to roam the earth. He named the genus
Gigantopithecus, meaning "gigantic ape," and the species
blacki, in honor of his late friend and colleague Davidson Black.

At the time of the discovery, during the 1930s, von Koenigswald
was working primarily in Java, unearthing fossils of human ancestors
and their relatives. China's unique fossil shops had already played
a major role in tracking down Homo erectus, which lived in Asia
between about one million and 300,000 years ago. Homo erectus remains
were first unearthed in Java in the 1890s, but pursuit of the source
of dragon bones subsequently led to a system of fossil-filled crevices
and caverns near the town of Zhoukoudian (Choukoutien), thirty miles
from Beijing. There, in 1929, a team of Chinese and Western scientists
discovered the first of a series of Homo erectus skulls that became
world famous as "Peking man."

The original fossils of Peking man disappeared during the confusion
of World War II - fortunately, after they were described and cast
by anatomist Franz Weidenreich. The war also caught up with von
Koenigswald, who was taken prisoner by the Japanese in Java. His
precious collection of Gigantopithecus teeth - at that point, the
only known specimens of the fossil ape - spent the war years in
a milk bottle buried in a friend's backyard on the island.

Photographed at the American Museum in the 1940's, German paleoanthropologists
Ralph von Koenigswald, left, and Franz Weidenreich, right, pose
with the skulls of apes, Homo erectus, and modern humans. The first
scientist to discover teeth of Gigantopithecus, von Koenigswald
correctly observed that they belonged to an ape, while Weidenreich
argued for their humanlike characteristics.

Meanwhile, however, Weidenreich, who had retreated from Beijing
to the American Museum of Natural History in New York, set about
studying plaster casts of the four teeth. Because of the unusually
large size of a few of the Homo erectus specimens from Java, Weidenreich
came up with the notion that there had been a period of gigantism
in human evolution, and that modern humans were the diminutive descendants
of these giants. In Apes, Giants, and Man, published in 1946, he
argued that the Gigantopithecus teeth were humanlike, and that von
Koenigswald had been mistaken in considering the animal an ape rather
than a member of the human family tree.

During von Koenigswald's wartime internment, Weidenreich's views
became widely accepted. To end the controversy that arose, more
complete specimens of Gigantopithecus had to be found, a task only
the Chinese could undertake, for the country was closed to Western
scientists. In the 1950s, with the establishment in Beijing of what
is now the Institute of Vertebrate Paleontology and Paleoanthropology,
Chinese paleontologists began to search for the source of the Gigantopithecus
fossils. Two veterans of the Peking man expedition, Pei Wenzhong
and Jia Lanpo, headed a team that visited the warehouses that supplied
all the apothecary shops in China with dragon bones and dragon teeth.
They found vast quantities of fossils in Nanning, the capital of
Guangxi Province. From there, they divided into two teams: one,
led by Pei, headed north; the other, led by Jia, went south.

At a Chinese pharmacy in Bangkok, the author (center) and archeologist
John Olsen (right) search among the medicinal "dragon teeth"
for interesting fossils.

Jia's paleontological detective work took him to southernmost Guangxi,
a karstic, or eroded limestone, region of great rock towers riddled
with caves. In the town of Daxin, which the local people said was
the source of all the fossils, they were directed to an old woman
who had, in her house, a bamboo tray full of fossils. One of them
was a Gigantopithecus tooth. She pointed out a very tall rock tower,
described by Jia as "a hundred meters straight up - almost
falling over, it was so steep." The mouth of a cave was clearly
visible behind a screen of brush.

A cave near the top of the rounded limestone tower at Liucheng,
China has yielded three Gigantopithecus jawbones and nearly a thousand
teeth.

Although it was four in the afternoon and raining hard when they
arrived, Jia says, "We were young, and couldn't be restrained.
We climbed straight up to that cave." That very day, Jia himself
found a Gigantopithecus tooth embedded in a hard, reddish matrix,
the first time that a paleontologist had discovered a fossil of
Gigantopithecus in a geological context.

Meanwhile, Pei was making a more momentous discovery to the north.
Word had reached the scientists of a giant jawbone discovered by
an old farmer in 1956 at a cave site called Liucheng. When Pei saw
the fossil, he was able to identify it at once as the jawbone of
Gigantopithecus, because it had all but three of its teeth still
attached. On a second visit, in 1957, Pei's team discovered the
first Gigantopithecus jawbone in place, in a very hard deposit resembling
red clay. Another was excavated in 1958. One of the jawbones was
extraordinarily large; presumably, it belonged to an adult male,
while the other two were thought to be from an adult female and
a juvenile.

In addition to the jawbones, Pei's group discovered nearly a thousand
Gigantopithecus teeth and numerous other mammalian specimens, including
some unusual dwarf varieties. Among them was a short-muzzled panda
half the size of the living giant panda. Chinese scientists have
recently suggested that this dwarf species was a direct ancestor
of the modern one.

The next development came in 1965 with the discovery of twelve
Gigantopithecus teeth at Wuming, a few hours' drive north of Nanning.
These teeth were significantly larger than their counterparts from
Liucheng, and the other animal fossils found with them suggested
that the site was considerably younger (current estimates are that
Liucheng is one million years old and that Wuming is between 300,000
and 400,000 years old). This suggested, first, that Gigantopithecus
was around as a species for a considerable period, and second, that
it may have become larger as the species evolved. This is a trend
seen in other large mammals that evolved during the Pleistocene
epoch, 1.8 million to 12,000 years ago.

A striking confirmation of both points was the discovery three
years later that a smaller, earlier form of the giant ape had once
inhabited northern India. In 1968, a farmer came forward with three
pieces of a jawbone he had found twenty-four years before, when
he was a boy of twelve working in his father's field. The specimen
was identified by primatologist Elwyn Simons as belonging to a distinct
species, Gigantopithecus giganteus, about half the size of Gigantopithecus
blacki. The new species was not only smaller but also more ancient,
coming from sediments that have been dated (by paleomagnetic reversals)
to about 6.3 million years ago.

The discovery of the jaws resolved, at least for most scientists,
any doubts that the creature was apelike and not, as Weidenreich
had argued, humanlike. Based on the fossils, Gigantopithecus is
now placed among the Asian apes, a descendant, along with the orangutan,
of the earlier ape ancestor Sivapithecus, best known from an 8-million-year-old
skull discovered in Pakistan. Its size and ape affiliation suggest
Gigantopithecus was a ground-dwelling, fist-walking creature.

While more teeth of the extinct ape have been found, no other bones
have turned up. Based only on the jaws and teeth, however, an attempt
can be made to reconstruct both the animal and its way of life.
The jaws are deep (top to bottom) and very thick. The molars are
low-crowned and flat, with very thick enamel caps suitable for heavy
grinding. The premolars are broad and flat and resemble molars.
The canine teeth are not sharp and pointed but shaped more like
what one would expect premolars to look like, while the incisors
are small, peglike, and closely packed. The canines and incisors
together form a specialized cutting tool, most similar to what is
found in some present-day tree sloths and in the extinct giant ground
sloth. The features of the teeth, combined with the massive, robust
jaws, lead to the inevitable conclusion that the animal was adapted
to the consumption of tough, fibrous foods by cutting, crushing,
and grinding them.

As a rule, large herbivores subsist on diets of coarse leaves and
grasses, which are low in nutritional value but typically available
in very large quantities. (Large animals succeed with this regime
partly because their metabolic requirements are relatively low,
in terms of energy required per unit of body mass.) One suggestion
is that Gigantopithecus, or at least the larger species in China,
was adapted, like the giant panda, to a diet of bamboo, the giant
grass abundant in the region. The jaws of Gigantopithecus and the
giant panda, if set side by side with the jawbones of, say, the
gorilla and the grizzly bear, appear thicker, deeper, and more massive.
These differences reflect the specialized diet of the panda (and,
by inference, of Gigantopithecus) compared with the much more general
diet of the gorilla and grizzly.

A further similarity between Gigantopithecus and the giant panda
is a high incidence of tooth cavities. Wu Rukang, in an encyclopedic
survey of the Gigantopithecus teeth in China, found cavities present
in 11 percent of them - an unusually high rate for an ape, but more
or less equivalent to the rate of dental cavities in the fossil
remains of the giant panda. Another Chinese researcher, Zhang Yinyun,
has reported a high incidence of hypoplasia - pitting in the tooth
enamel that indicates periods of arrested development. These may
be a result of disease or food shortage. While no certain conclusion
may be drawn, we do know that bamboo is subject to periodic die-offs,
which produce food shortages that threaten the survival of the giant
panda.

A more direct line of evidence that could be pursued regarding
the diet of Gigantopithecus was pointed out to me by Bob Thompson,
a graduate student in New World archeology, who attended one of
my lectures about the extinct ape. He suggested we might look at
the teeth for adhering phytoliths, microscopic pieces of silica
found in many plants. The existence of phytoliths has been known
since the early nineteenth century, and scientists had already successfully
looked for them on stone tools, to which they apparently bond physically
by the combined action of friction and moisture. But it was the
first time, as far as I know, that anyone had suggested looking
for them on fossil teeth.

Four teeth were borrowed for study from the British Museum (Natural
History) and the Senckenberg Natural History Museum in Frankfurt:
an upper incisor, lower canine, lower premolar, and lower molar.
After the teeth were cleaned to insure that what we found was definitely
part of the fossils, they were examined under a scanning electron
microscope at the University of Iowa by Smithsonian paleoecologist
Dolores Piperno. At least thirty phytoliths were found on the teeth,
most of them on the molar. We also detected tiny scratches apparently
left by phytoliths, which are harder than tooth enamel. In one case,
we found a phytolith sitting astride the end of the track it had
plowed into the tooth - like a sled stopped in its path in the snow.

A photomicrograph shows a silica fragment bonded to a tooth of
the fossil ape. Its shape indicates that it came from grass, possibly
bamboo. Color enhancing isolated the silicified mass of plant cells
and, within it, the impression of a single cell.

More than half of the phytoliths we observed were long and needlelike
and could be attributed to the vegetative part of grasses, possibly
bamboo. The rest were conical or hat shaped, attributable to the
fruits and seeds of dicotyledons. Piperno tentatively identified
them as fruits from a tree of the family Moraceae, quite possibly
durian or jackfruit, both of which are common throughout tropical
Southeast Asia. This proved that Gigantopithecus had a varied diet,
although we still suspect that bamboo was its staple food.

What other conclusions can be drawn about the extinct ape? An outstanding
characteristic of giant herbivores is their extreme slowness. They
have no particular need of speed: their size and thick skins protect
them from predators, and of course their feeding habits require
no more of them than that they move from place to place as they
systematically denude the landscape of vegetation. Furthermore,
they are usually stuffed full of bulky food to digest, which tends
to produce inertia. Gigantopithecus probably followed this pattern.

Finally, the adult males of the giant ape were much larger than
the females. Australian anatomist Charles Oxnard statistically analyzed
735 teeth of Gigantopithecus that were complete enough to be measured
accurately. He found that they divided neatly into two size groups
of equal number, which he interpreted to represent the males and
females in the population. The contrast was greater than that seen
in any living primate species, including the gorilla and the orangutan,
two species in which the male is substantially bigger than the female.
In Gigantopithecus, the difference in tooth size between the sexes
may represent strong competition among males for mates - a clue
to the species' social behavior.

The largest of the jaws, along with some of the teeth, are compared
at with modern human remains.

To gain a more complete image of what the giant ape looked like,
we sought the help of Bill Munns, who creates highly realistic,
life-size models of existing endangered primates - gorillas, orangutans,
and the Chinese golden monkey - for zoos and educational institutions.
Based on the jaws and teeth, and using the proportions of the skulls
of existing great apes, we estimated that the average male Gigantopithecus
had a skull that measured eighteen inches from the bottom of the
jaw to the highest point of the sagittal crest (a male gorilla,
for comparison, has a skull ten inches high).

The next step was to project a hypothetical skeleton from the hypothetical
skull. For this purpose Munns used as references two of the largest
terrestrial primates known: one modern, the gorilla, and one from
the fossil record, the extinct giant baboon Theropithecus oswaldi.
In determining the size of Gigantopithecus, we felt it necessary
to scale the body back a bit, so as not to be influenced too much
by the giant ape's extraordinarily deep and thickened mandible.
Nevertheless, given that the average male silverback gorilla is
about six feet tall (standing erect) and weighs in at 400 pounds,
Munns calculated that the average Gigantopithecus male was more
than ten feet tall and weighed as much as 1,200 pounds - comparable
to a large male polar bear.

Bill Munns stands next to his model of a Gigantopithecus male,
a quadrupedal, fist-walking creature that also could have stood
erect, as bears do.

One intriguing question is what contact our remote ancestor, Homo
erectus, may have had with the giant ape. That the two coexisted
for some time in the same region is supported by direct evidence.
In 1965, Vietnamese paleontologists discovered the remains of both
creatures at Tham Khuyen, a cave site in Lang Son Province, near
the Chinese border. Chinese excavators followed suit, excavating
Gigantopithecus and Homo erectus side by side in Hubei Province
in 1970 and more recently, in 1987, in Sichuan Province.

Gigantopithecus was native to southern Asia, while Homo originated
in Africa about 1.6 million years ago and migrated eastward, finally
arriving in what is now Southeast Asia about one million years ago.
The opportunity to explore this nexus attracted archeologist John
Olsen and me to Vietnam. One reason we did not choose to go to China
was that all the promising sites had been reserved by Chinese paleoanthropologists,
and we doubted we would find a new site in a region that had been
so thoroughly mined. In contrast, Vietnam had no history of exploiting
fossil-rich caves for dragon bones. And so in January 1989 we found
ourselves probing four caves at the base of a karst tower near the
hamlet of Lang Trang, about 100 miles southwest of Hanoi, as part
of a joint American-Vietnamese expedition.

The caves had seemed promising in our preliminary survey the previous
May, and as we began work, even local children brought us fossil
mammal teeth (although we tried to discourage them), which they
retrieved from an underground stream by squeezing through a crevice
in the cave we called Lang Trang I. Meanwhile, we began cutting
out blocks of breccia, the sediment typical of caves, which is gradually
formed by material washed or otherwise transported into a cave and
cemented with limestone dissolved from the cave walls and ceiling.

The fourth day of our dig, Friday the thirteenth, turned out to
be a lucky one: within the main deposit I found a lens-shaped vein
of dark, sandy sediment that was unusually rich in fossils. The
material had probably washed into the cave from the nearby Ma River,
which in ancient times meandered right alongside the karst tower.
Perhaps a violent monsoon had caused the river to overflow its banks
and flood the cave. After the waters receded, the slow process of
breccia formation began again, sealing the sandy lens within Lang
Trang I.

We immediately set to work cutting out hunks of the sandy deposit,
revealing a small chamber that we surmised was the source of all
the fossils the children had been bringing us. Our finds included
barking deer, a musk deer the size of a big dog; sambar, a large
deer with three-pointed antlers; wild boar; and giant panda. A huge,
ridged molar, weighing several pounds and belonging to Stegodon,
an extinct relative of the elephant, assured us that we were dealing
with a Pleistocene site that might also contain Homo erectus and
Gigantopithecus. One softball-sized sample of this deposit was later
analyzed at the University of Iowa, revealing that it also contained
some small teeth and fragmentary limb bones of a diverse microfauna,
including rodents, reptiles, fishes, and riverine sponges. These
fossil fragments were about the same size as the coarse sand particles
they were mixed with.

Then, on January 18, 1989, Nguyen Van Hao made a key discovery:
in the floor of the fourth cave he found a premolar of Homo. Since
it was an isolated tooth, we found it difficult - impossible, really
- to identify the species. Since then, four additional teeth of
Homo have been recovered from caves I, II, and IV. Subsequently,
a boar tooth from cave I has been dated (by a method called electron-spin
resonance) to about 480,000 years ago. Given this preliminary date,
the specimens should be assigned to Homo erectus. The discovery
helps fill the gap between Zhoukoudian, in northern China, and Java,
more than 3.000 miles to the south.

We now have a fairly complete picture of the Pleistocene environment
of Lang Trang. The jungle vegetation would have been more lush,
but not startlingly different. The fauna, however, would have been
striking, with huge beasts of all kinds dominating the landscape.
Carnivores such as the tiger and leopard were much more common then
and competed for food with species, such as the Asiatic black bear,
that have entirely disappeared from Vietnam. And they all competed
with the wolf and the Asiatic wild dog in preying on the dozens
of bovid and cervid species (cowlike and deerlike mammals). Also
present were the rhinoceros and elephant (both now rare) and the
stegodon, as well as the orangutan and tapir, both now extinct in
Vietnam. The giant panda, also now vanished, chomped its way through
the bamboo stands. Taken in this context, Gigantopithecus was no
freakish monstrosity, but simply the primate example of a Pleistocene
phenomenon.

Primates make up 13 percent of the total fauna in our collection.
At least five genera are accounted for: two types of macaque monkey,
orangutan, langur monkey, gibbon and Homo. So far we have been disappointed
only by the absence of Gigantopithecus.

Sometime near the end of the middle Pleistocene, perhaps 200,000
years ago, Gigantopithecus became extinct. The animal had flourished
for at least six million years, quite a respectable figure, but
it went the way of a great many genera of every shape and size.
At about the same time, the giant panda disappeared from much of
its original territory, notably insular southeast Asia, until it
now survives only in the cold upland regions of Sichuan Province.
The best guess as to what caused the panda's extinction in Southeast
Asia is human hunting: even now the animal is hunted for food and
for pelts, despite the best efforts of the Chinese government to
discourage the practice. Similarly, human hunting may have led to
the demise of Gigantopithecus.

Munching on bamboo, a giant panda survives on a diet that may resemble
that of Gigantopithecus.

Environmental change may also have been a contributing factor,
just as the bamboo die-off in China in the 1970s nearly wiped out
the remaining population of giant pandas, with fewer than a thousand
estimated to have survived. Or by eating the tender bamboo shoots
and exploiting the plant for other purposes, including toolmaking,
humans may have outcompeted the giant ape for this critical resource.
The competition from both humans and the giant panda may have been
too much.

Gigantopithecus is gone. Or is it? Following the publicity about
our research in Vietnam, I have received several letters from veterans
who say that they came face to face with huge, hairy apes in the
Southeast Asian jungle when they were posted in Vietnam. And of
all the theories advanced to provide a zoological identity for Bigfoot,
the Abominable Snowman, and other elusive creatures, perhaps the
most popular is that they are none other than Gigantopithecus, still
alive in relict populations (relict populations of Neanderthal man
run a close second). While these contemporary reports are probably
false, we can contemplate the time when our remote ancestors did
encounter the giant of all apes in the tropical rainforests of Southeast
Asia.